Are you sure you mean [ and ] here? They signify character classes (much like how \d means [0-9], or "any one digit", [WS] means "any one W or S"), not capture groups. Assuming you meant (WS|76), then do you really want to capture the (WS or 76) separately from whatever follows? My guess is that you meant ((?:WS|76)).*?) here — and I doubt you actually need to specify that this substring begins with the WS or 76, so why not just simplify it to (\S+)?

\s+(.*)\s+(.*)

I'm not sure which parts of the sample data this would match. Did you really intend to have it there?

Modifying your regex according to the above assumptions, and tacking on a $ for good measure, I come up with /^\s*(\d+)\s+(.+?)\s*(\S+)\s+(\w+)$/. Furthermore, I threw in a chomp because I don't want to be bothered with the newlines that are tacked onto each value for $_, so eventually my version of your script looks like this:</c>